The detector upgrade program of the STAR experiment at RHIC at BNL

The Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is a unique facility, which allows studying the collision of different nuclei and polarized protons at variable energy. The spin physics program at RHIC at BNL focuses on the collision of polarized protons at a centre-of-mass energy of 200-500 GeV to gain a deeper understanding of the spin structure and dynamics of the proton. The relativistic heavy-ion program studies the behavior of matter under extreme conditions in Au-Au and d-Au collisions. Recent results provide strong evidence for the formation of a new state of strongly interacting matter. The long-term program, to study quantum chromodynamics (QCD) at RHIC in further detail, requires various upgrades and additions to the existing STAR detector over the next 10 years, which is the main focus of the following paper.